1. Field of the Invention
The present invention relates to a transport mechanism preferably employed in a library apparatus such as a magnetic tape library apparatus, for example. In particular, the invention relates to a transport mechanism including first and second mobile carriers accessible to individual cells defined in a storage.
2. Description of the Prior Art
As disclosed in Japanese Patent Application Publication 10-255373, a library apparatus sometimes includes first and second mobile carriers accessible to individual cells defined in a storage. The library apparatus includes a first controller circuit connected to a power source of the first mobile carrier. A second controller is connected to a power source of the second mobile carrier. The movement path of the first mobile carrier partially wraps over the movement path of the second mobile carrier.
For example, when the first mobile carrier is urgently stopped based on the instructions from the second controller circuit, the first controller circuit cannot control the first mobile carrier. The first mobile carrier cannot move at all. The first mobile carrier thus interferes with the movement of the second mobile carrier. Unless the first controller circuit is started again, the second mobile carrier cannot return to the operation. The library apparatus is expected to always operate without any interruption.